Bunk bed frame



FIG. 1 is a front elevation showing the bunk bed frame;

FIG. 2 is a rear elevation showing the bunk bed frame;

FIG. 3 is a left side elevation of the bunk bed frame;

FIG. 4 is a right side elevation of the bunk bed frame;

FIG. 5 is a top plan view of the bunk bed frame.

The ornamental design for a bunk bed frame, substantially as shown anddescribed.